Tuning dial assembly for electrical apparatus



July 6, 1954 R. M. JENSEN ET AL TUNING DIAL ASSEMBLY FOR ELECTRICALAPPARATUS Filed Dec. 27, 1951 .R. M JENSEN INVENTORS- C. SAMEK A TTORNEVPatented July 6, 1954 UNITED orFl-ce APPARATUS Rhineliardt M.- Jensenand Charles T. Samek,

Berkeley: Heights; N. J phone.- Laboratories, Incorporated, New York,,.Nell a-colzporation-of N ew Y orkx Application Decemlier27, 1951, SerialNo. 263,667

2: Glai'ms; (Cl. 116-1241) 1. This invention relates to tuning dialassemblies andJnore particularly to such. assembliesrw-herein a.longitudinal reciprocal" tuningv elementrmay be selectively. moved toaccurately predetermined positions.

An object of this invention the provision of a dial assembly for usewith adjustable elec-,

trical apparatus wherein reciprocal axial motion, imparted to anoperating shaft by a central knob, is converted to a calibrated circularmotion.

In the preferred embodiment of our invention, the dial assemblycomprises a sleeve member, having a longitudinally extending centralbore therein, fixedly secured to and projecting from the face of asuitable apparatus panel. The central bore of the sleeve, at its freeend, is of reduced diameter and is internally threaded, and the outersurface thereof is provided with a helical groove having a substantiallylong lead, which extends the length of the sleeve. Positioned in thecentral bore of the sleeve, and having its outer endin threadedengagement with the outer end of the sleeve, is an operating shaft whichis operatively connected to suitable apparatus mounted on the rear ofthe panel.

Rotatably mounted on the sleeve and having an internally extending pinin engagement with the groove on the outer surface of the sleeve, is ashouldered hub member which has secured to its inner end an indicatingdial plate. Mounted on the reduced diameter portion of the hub member,bearing against the shoulder and secured, as by a press fit, is asuitable bearing which is secured, also as by a press fit, in a recessin the rear of a knob member which is positioned on the outer threadedend of the shaft, and is secured thereto by a suitable nut located in arecess in the outer face of the knob.

In operation, when the control knob is rotated, either clockwise orcounter-clockwise, the shaft will move axially With a reciprocatingmotion. Since the indicating dial is secured to the hub member, which,in turn, is rotatably mounted on the sleeve and in engagement with thegroove therein which has a long lead, and since the shaft will travel inthe fine threads in the sleeve, the knob will complete severalrevolutions to a single revolution of the dial depending on the pitch ofthe groove on the sleeve, thereby causing the apparatus attached to theshaft to reciprocate and be finely adjusted.

Other objects and advantages of this invention will be apparent from thefollowing detailed description when read in connection with thefollowing drawings wherein:

assignors to Bell Tele Fig. 1 is a side elevational view, partlyirrsection of an assembly'constructed' in accordance: with thisinvention, and illustrates the contrcl knob at the end of'its outwardtravel;-

Fig; 2 is aview similar to Fig. 1 but shows the control knob-at theendof itsinward travel;- and Fig. 3 is a front elevational view, to areduced scale, of the knob and indicating dial.

As shown in the drawings, there is mounted on the face of the apparatuspanel I0, a shouldered sleeve member I I, which is secured in positionin a suitable aperture in the panel by abutting the shoulder against thepanel and spinning into contact with the panel the extending portion ofthe sleeve. The sleeve l I is provided with a central bore I2 which hasa reduced diameter portion I3 at its outer end and is provided with thefine internal threads I4. Theouter surface of the sleeve I I is providedwith a helical groove I5 which has a long lead and extends substantiallythe full length of the sleeve H.

Rotatably mounted in the central bore I2 of the sleeve II, and havingits threaded outer end I 6 in engagement with the threads I 4 on thesleeve I I, is the operating shaft I I which is operatively connected tothe adjustable member [8 of the capacitor l-9 which is enclosed in thehousing 20 mounted on the rear of the panel l0.

Journaled on the sleeve II and having an internally extending pin 2 I,in engagement with the groove I5 on the sleeve II, is a shouldered hubmember 22 which has secured to its inner end, by means of screws 23, anindicating dial plate 24, provided with suitable indicia, as shown inFig. 3, arranged to register with the index pin 25 located on the panelI0.

Secured on the reduced diameter portion of the hub 22, against theshoulder, by means of a press fit, is the ball bearing 26 which is alsosecured by a press fit, in the recess 21 located in the rear of the knob28. The knob 28 is in threaded engagement with the outer threaded end IBof the shaft I1, is secured thereto, and locked in position by means ofthe jam nut 29 located in the recess 30 in the front face of the knob28. A suitable collar 3| is secured on the shaft IT to limit the outwardmovement of the shaft and its associated elements.

When the control knob 28 is rotated, either clockwise orcounter-clockwise, the shaft I! will move axially due to the engagementof the threaded end J 6 with the fine internal threads I4 in the frontend of the sleeve II. Since the dial plate 24 is secured to the hub 22,which is rotatably mounted on the sleeve II with its pin 2| inengagement with the groove l5, which has a substantially long lead, andthe shaft I! will travel in the fine thread ll of the sleeve H, the knob28 will complete several revolutions to .a single revolution of the dialplate 24, the number depending upon the ratio of the pitch of the thread14 to the itch of the groove Hi.

It will thus be observed that the movable element 18 of the capacitorl9, attached to the shaft I1, will be caused to reciprocate and thecapacitance will be finely controlled. A wide range of adjustment isindicatable by the dial because of the limited rotation of the latterrelative to the knob.

Although we have shown and described a preferred embodiment of ourinvention it is to be understood that various modifications may be madetherein without departing from the scope and spirit of the invention.

What is claimed is:

1. A tuning dial for electrical apparatus comprising a support, a sleevehaving a fine internal thread and an external helical groove secured tosaid support, a shaft in engagement with said internal thread, a hubrotatably mounted on said 25 sleeve and in operative engagement withsaid external helical groove, a knob rotatably mounted on said hub andsecured to said shaft for causing the rotation thereof and a dial platesecured to said hub.

2. A tuning dial for electrical apparatus comprising a support, a sleevehaving a fine internal thread and a coarse external helical groove,secured to said support, a shaft in engagement with said fine internalthread, a hub rotatably mounted in said sleeve and having an internallyextending pin in engagement with said external helical groove, a bearingsecured on said hub, a knob mounted on said bearing for rotatablysupporting said knob, said knob having one end I of said shaft securedtherein for causing the rotation thereof and a dial plate secured tosaid hub.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,622,389 Miessner Mar. 29, 1927 1,725,639 Herman Aug. 20,1929 1,733,337 Deutscher Oct. 29, 1929 1,836,583 Elliott Dec. 15, 1931

